Antipruritics (anti-itch medications) have been used for years for a variety of causes, but the world lacks a safe treatment that will provide relief for most or all of these nuisance or painful conditions.
Antihistamines such as diphenhydramine (Benadryl), corticosteriods such as 1% hydrocortisone cream on the OTC market and Topicort 0.25% or 0.05% desoxymetasone by prescription, local anesthetics such as benzocaine topical cream (Lanacane®), and counter-irritants such as mint oil, menthol or camphor have been used. Dilute ammonium hydroxide is marketed for use on mosquito bites, where it can neutralize the acid component of the sting. Benzyl alcohol and pramixine hydrochloride are often used at 10% and 1% concentrations respectively. Benadryl® is an itch stopping spray containing active ingredients identified as diphenhydramine hydrochloride 2% as a topical analgesic and zinc acetate 0.1% as a skin protectant, and reference is made to its use for insect bites, poison ivy, mosquito bites, sunburn and minor cuts and scrapes.
Most of these skin treatments use a small amount of active ingredients in a medium of mineral oil or petroleum jelly, such as Vaseline brand petroleum jelly, or water as the carrier. Glycerol (as named by chemists) or glycerin (as it is called by pharmacists) and propylene glycol are used as carriers for the active ingredients in some commercial skin treatments. Water is a frequent component or main carrier, as in the case of Epsom salts (i.e., magnesium sulfate or magnesium sulphate) or ammonia.
Hydrocortisone creams are used commonly as multi-purpose treatments for itching, but these creams often have severe adverse side effects. Packages of Over the Counter (OTC) hydrocortisones generally indicate to discontinue use after 1 week, but even dermatologists prescribe longer term usage for skin problems such as eczema. Unfortunately, continued use of these steroids can lead to addiction and higher dosages are needed to obtain relief, until the patient experiences what some call “elephant skin” and very painful withdrawal, with oozing, shedding and itching can last up to 24 months for complete recovery and return to normal skin. The International Topical Steroid Addiction Network addresses recovery from this problem at www.itsan.org. Drs. Marvin Rapaport and Mototsugu Fukaya have treated thousands of patients undergoing painful withdrawal from such addiction in the U.S. and in Japan. “Corticosteroid Addiction and Withdrawal in the Atopic: The Red Burning Skin Syndrome” discusses this topic in detail in Clinics in Dermatology, 2003; 21:201-214. Thus, there is now a desperate need for a multi-purpose safe alternative to the use of corticosteroids.
Antihistamines are used sometimes for treatment of bee and wasp stings, as these often cause allergies. Some folks are allergic to Benzocaine in products such as Lanacane, which sometimes is a cause for itching of skin or headaches, according to the Mayo Clinic.
Calamine lotion and Epsom salt solutions have been used for many years for treatment of itching skin; their limitations and possible benefits are discussed below.
The chemistry for some of the itch causes is known, and it remains a mystery for some. The leaves of poison ivy, poison sumac and poison oak, for example, are known to transfer urushiol to the skin. Urushiol is a catechol (double hydroxyl groups on a benzene ring) with an adjacent hydrocarbon with 15 to 17 carbons, some saturated, some with single, double or triple unsaturation groups.
Both the acid and the unsaturation groups may be responsible for the itching of this compound. Potassium permanganate was once recommended as a treatment for poison ivy, perhaps intended to oxidize the unsaturations. This purple coloration transitioned quickly to brown manganese oxide and was less effective than desired on the young skin of this inventor seventy five years ago. Rapid treatment with soapy water (within 10 minutes of contact) can prevent the rash of poison ivy, but wash basins are rare along hiking trails. In contrast to the “unsaturation” theory, linseed oil has been used for many years without causing irritation such as poison ivy.
U.S. Pat. No. 5,443,847 discloses a treatment for poison ivy using divalent manganese compounds in aqueous solution. The patent states that divalent manganese ions couple with the ortho-position hydroxyl radicals and thereby detoxify the urushiol. If true, this might be the mechanism for effectiveness with other multivalent cations such as magnesium, calcium and zinc for this specific skin injury.
Insect bites and stings usually inject one or more nasty chemicals into the blood. A female mosquito does damage by injecting her saliva into the victim's blood steam in order to reduce the blood's viscosity for an easier suck back into her belly. Mosquito saliva contains about 20 proteins, including components to minimize vascular constriction, blood clotting, and platelet aggregation, and enzymes that aid in sugar feeding. Female biting midges (Dipteran), often called sand flies, also need protein from animal blood for their eggs. They often carry viruses or visceral leishmaniasis, a parasite almost as deadly as malaria. Spider bites may introduce a venom into the skin.
The itch from Psoriasis can be very painful and the sources can sometimes be life-threatening. This invention does not presently claim to heal any diseases associated with itching, but neither does it preclude such possibilities, and future clinical tests may show such efficacy. However, a number of users of the Example formulations cited below have brought appreciative response from users who have treated a variety of ailments and injuries to the skin.
Persons affected by shingles would hardly call their pain an itch. This herpes zoster is known to be caused by surprising reactivation of dormant virus from chicken pox many years earlier in one's life. Rashes and blisters may form along with the very painful viral attack on nerve ends. Treatments may include antivirals such as acyclovir, famiclovir and valacyclovir, taken in pill form or by intravenous injections, and corticosteroids may be attempted to reduce swelling and local pain. An online reference from the National Institutes of Health mentions that calamine lotion, colloidal oatmeal or starch baths may help to relieve the itching and discomfort (ref. www.ncbi.nlm.nih.gov/ubmedhealth/PMH0001861/).
The old-time anti-itch treatments of Epsom salts (magnesium sulfate solution in water) and calamine lotion (calcium hydroxide solution, and zinc oxide dispersion in water, sometimes with a tint of ferric oxide) are of particular interest. This inventor suspects that these formulations are very limited in ability to deliver any useful chemicals to nerve endings. Their deficiencies are in the use of water for delivery of the cations. Water does not readily penetrate the skin, lest swimmers and bathers become balloons or become Michelin Men. These multivalent cations are shown by this invention to be more effective when delivered by a carrier in which they are soluble that can penetrate the epidermis barrier better than water.
The USP formula for calamine lotion is as follows:
Zinc oxide, 80 grams
Bentonite magma, 250 ml (thickener)
Glycerin, 20 ml
Calcium hydroxide, saturated (1.7 gm) solution in water to make 1 liter
This liter of solution has only 0.022 mols of calcium and virtually no zinc ions in a water/glycerin solution which has an effective solubility parameter of 46.5 Pa0.5. The zinc oxide is insoluble, thus forms no zinc ions and can not permeate the epidermis to reach nerve endings. Thus the zinc ion is expected to have negligible effect on any nerve endings, but a small amount of calcium ion might penetrate the skin barrier and reach nerve endings, as a small amount of water penetrates the epidermis.
Epsom salt (magnesium sulfate heptahydrate) has been known since 1618 when Henry Winkler in Epsom, England, promoted its natural waters used as a “feel good” bath. Calamine lotion has been known in the U.S. since the early 1830s and has been used as a home treatment for a variety of itches. In 1992 the Federal Drug Administration declared that it had not been proven to be effective and banned it from the market with any healing claims. In 2008, the FDA relented to recognized usage and approved its use as a “skin protectant” for treatment for plant poisons, but with no clarification whether the calcium or the zinc component or the combination of these was Active.
The historical effectiveness of these two products, though used in the disadvantageous medium of water, raises the issue of why has not research occurred within the multi-million-dollar budgets of companies in the skin care business. Insight into this history and into the physical chemistry of mass transfer through the epidermis has provided the stimulus for creation of new formulations described herein.